I think it's not fair to generalize all newbies or newly made accounts and deprive them all. What Ithink is best is to consider a senseless post of a newbie as a spam and just report it to a mod and explain why it should be deleted.
Thing with bumps is that they work on the spot, they put a post on top and the newly created account is at no risk since being banned isn't a concern for them and it also takes some time.
Users below Jr. Member are already not able to vote, it takes very little effort to reach that rank. If you're a honest forum member it shouldn't worry you.
It might be worth checking IPs, or using cookies to look for alt accounts. Both checks can be circumvented, but you might catch a few offenders.
Cookies are not that hard to erase or bypass completely by opening (or sandboxing) a new instance. As of IPs there already are some limits in place. Like points of evil, maximum requets per second and post cool down.